Outer pipe sleeve for a sea floor mooring pile

ABSTRACT

The present disclosure provides an improved system and method for increasing an anchoring force on a pile. The concepts regarding the pile can apply whether the pile is degraded and no longer able to support its intended load, or a load on the pile has increased to a level that may overstress the pile. A sleeve can be installed even in subsea conditions over the pile and can be used to provide an additional securing force to the existing pile. The sleeve may include its own padeye for coupling an anchor line or other coupling member to a structure to be secured. The sleeve may also include an assembly of rings coupled together with at least one longitudinal member. The assembly with the rings spaced a distance away from each other may help reduce an installation friction on the sleeve, as it is installed into the sea floor.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND

1. Field

The disclosure relates to pile anchor systems and methods, andparticularly to pile anchor systems and methods for offshore petroleumstructures, such as floating structures, drilling or production risers,and other marine structures.

2. Description of Related Art

Often marine structures used in offshore petroleum industry are mooredto a pile that is anchored to a sea floor. The pile is generally atubular element that is installed into seabed deposits that form the seafloor. Depending on the depth of the sea at a given location, variousmethods can be used to install the pile into the sea floor. At greatdepths, it may be problematic to use a pile-driving hammer or otherequipment to install the pile.

A type of pile, known as a suction pile, is particularly suitable fordeep water development. Generally, a suction pile is a tubular elementwith a closed top and open bottom that is installed vertically into thesea floor by self weight penetration and suction pressure. FIG. 1 is across-sectional schematic diagram of a pile installed into a sea floor.The suction pile, pile 2, may be installed in the sea floor 4. The pile2 includes a top 6, sometimes known as a “pile cap,” attached to tubularsides 8, and is open at the bottom 10. The top 6 can include a valve 12that gives access to the interior volume 11 of the pile 2 between thesides 8 and the top 6. The pile 2 further includes a padeye 14. Thepadeye 14 generally is a reinforced section used to attach an anchorline or other coupling member 16 to a structure (not shown) that mayneed mooring or otherwise securing. The installation technique generallyincludes locating the pile 2 in an appropriate location and lowering thepile into the sea floor 4 with cables. Typical the pile will penetrateunder its own weight into the seafloor deposits until the resistancefrom the seabed deposits equals the self weight. Water can then bepumped out of the pile through the value 12 to create a differentialpressure in the volume 11 with a net downward force to push the pile toa desired depth of full penetration.

The pile 2 can have different configurations. Some piles may includeexternal fins that extend outwardly from the side. Other piles caninclude internal baffles or stiffening members that, for example, can beselectively depressurized to position the piles at different anglesrelative to the sea floor. Some designs have hemispherical tops. Otherpiles include groups of suction piles coupled together to form anassembly.

A suction pile, driven pile or any other tubular structure penetratedinto the seabed to support or resist loads is referred to generallyherein as a pile.

Piles can become damaged, worn, or otherwise degraded. Presently, whensuch piles degraded, the pile is either removed, or abandoned, andanother pile is installed at another location near the first pile. Ingeneral it is considered that after the initial installation of a pile,the sea floor 4 has been disturbed and the shear resistance around theinstalled pile may be significantly reduced. Typically, the sea floordeposits 4 may require several months of consolidation and recoveryafter a pile is installed to provide full strength to the anchoring ofthe pile in the sea floor deposits.

Further, there are times in which an existing pile may be in asatisfactory condition, but may require to resist additional structuralloads from a new design load case or change in design. These new designload cases may overstress or be beyond the capacity of the existingpile. Typically, the solution has therefore been to install anadditional pile to provide further support or replace the existing pile.However, the new solution still has the disadvantage of not providingfull support until some later time, when the disturbed layers on the seafloor 4 can consolidate around the pile.

Therefore, there remains a need to provide additional support to a pileeither in a degraded condition or to provide additional support toextend the capacity of the existing pile.

BRIEF SUMMARY

The present disclosure provides an improved system and method forincreasing an anchoring force on a pile. The concepts regarding the pilecan apply whether the pile capacity has been degraded and no longer ableto support its intended load, or a load on the pile has increased to alevel that may overstress the pile. A sleeve can be installed even insubsea conditions over the pile and can be used to provide an additionalsecuring force to the existing pile. The sleeve may include its ownpadeye for coupling an anchor line or other coupling member to astructure to be secured. The sleeve may comprise a tubular sleeve orinclude an assembly of rings coupled together with at least one or morelongitudinal members. An pile sleeve assembly with rings spaced adistance away from each other can help reduce the installation frictionon the sleeve, as it is installed into the sea floor.

The disclosure provides a method for rehabilitating an existing pileinstalled into a sea floor, comprising: positioning a pile sleeve havinga padeye; allowing the pile sleeve to be lowered over the pile; andsecuring the sleeve to the pile.

The disclosure also provides a rehabilitation system for a subsea anexisting pile, installed into a sea floor, the system comprising: asleeve having a outer shell forming an interior volume and at leastpartially open on a bottom of the sleeve; a padeye coupled to thesleeve, the padeye having a section of material coupled to the sleevewith an opening disposed through the material; and the sleeve beingadapted to be inserted over a pile.

This disclosure in addition provides a rehabilitation system oftransferring new or additional loading on the existing pile at a pointeither at the top, bottom or any selected location between the top andbottom of the pile sleeve system.

BRIEF DESCRIPTION OF THE DRAWINGS

While the concepts disclosed herein are susceptible to variousmodifications and alternative forms, only a few specific embodimentshave been shown by way of example in the drawings and are described indetail below. The figures and detailed descriptions of these specificembodiments are not intended to limit the breadth or scope of theinventive concepts or the appended claims in any manner. Rather, thefigures and detailed written descriptions are provided to illustrate theinventive concepts to a person of ordinary skill in the art as requiredby 35 U.S.C. §112.

FIG. 1 is a cross-sectional schematic diagram of a suction pileinstalled into a sea floor.

FIG. 2 is a cross-sectional schematic diagram of a system for supportinga pile sleeve installed in a sea floor.

FIG. 3A is a cross-sectional schematic view of the sleeve system with asupplementary support system.

FIG. 3B is a cross-sectional schematic view of an alternativesupplementary support system.

FIG. 3C is a plan schematic view of the supplementary support system.

FIG. 4 is a perspective schematic view of another embodiment of thesleeve.

FIG. 5 is a side schematic view of an alternative embodiment of thesleeve shown in FIG. 4.

FIG. 6 is a top schematic view of a lower ring shown in FIG. 5.

FIG. 7 is a top schematic view of an upper ring shown in FIG. 5.

FIG. 8 is a perspective schematic view of another embodiment of thesleeve.

DETAILED DESCRIPTION

One or more illustrative embodiments of the concepts disclosed hereinare presented below. For the sake of clarity, not all features of anactual implementation are described or shown in this application. It isunderstood that in the development of an actual embodiment, numerousimplementation-specific decisions must be made to achieve thedeveloper's goals, such as compliance with system-related,business-related and other constraints, which vary by implementation andfrom time to time. While a developer's efforts might be complex andtime-consuming, such efforts would be, nevertheless, a routineundertaking for those of ordinary skill in the art having benefit ofthis disclosure.

FIG. 2 is a cross-sectional schematic diagram of a system for supportinga pile installed in a sea floor. The pile 2, having a padeye 14, isinstalled at least partially in a sea floor 4. Due to degradedconditions, additional loading, or other circumstances, the pile 2 maynot be suitable for supporting an intended load. A sleeve 20 can beinstalled over the pile 2 to provide additional support for the load.

The sleeve generally includes a sleeve cap 26 as a top of the sleevecoupled to an outer shell 28 with at least a partially open bottom 30 toform an interior volume 31. The sleeve 10 may generally include a padeyering 22, which may be integral with or separate from an upper portion ofthe sleeve 20. The padeye ring 22 generally includes a sleeve padeye 24coupled thereto. The pile, sleeve, and rings are shown having a circularcross-section. However, it is to be understood that other geometriccross-sections can be used and are contemplated, including square,rectangular, octagonal, hexagonal, elliptical, and other cross-sectionalshapes as may be appropriate. Such shapes are included within the term“tubular,” “rings,” “annular,” and other shape-referencing terms usedherein. Any annular space 32 formed between the exterior of the pile 2and the interior of the sleeve 20 can be filled with grout, if desired.

The sleeve 20 can be secured to the pile 2 by a number of methods knownto those with ordinary skill in the art. For example, depending on theangle of force exerted on the sleeve, and frictional forces between thesleeve and the pile 2 and/or sea floor 4, the sleeve may beself-securing to the pile. The frictional forces between the sleeve andthe pile, or even the sleeve and the sea floor materials, may “lock” thesleeve to the pile, so that relative vertical movement is restrained. Inother circumstances, the sleeve may be secured by grouting, adhesives,or other chemical/mechanical means. Still further, a locking system 34can include welding the sleeve to the pile, inserting a pin through anopening in the sleeve and/or pile, using a threaded nut, or other means.Thus, in at least one embodiment, the sleeve cap 26 can be at leastpartially open to allow a portion of the pile to extend through thesleeve 20 to lock the sleeve to the pile.

The sleeve may be used to rehabilitate the degraded pile by proving anew coupling location with a new padeye for the coupling member.Further, the sleeve can be used to expand the effective surface area ofthe pile to provide greater resistance in the sea floor and greaterability to support loads from the coupling member on the pile thatwithout the sleeve.

A coupling member 36 can be coupled to the sleeve padeye 24. Thecoupling member 36 can be coupled to a structure 38 such as a tensionleg platform, semi-submersible platform, or other structures as may beappropriately moored or otherwise secured to a pile. The coupling membercan include, without limitation, cables, chains, and other anchor lines,such as in catenary or taut-line applications, known to those withordinary skill in the art.

FIG. 3A is a cross-sectional schematic view of the sleeve system with asupplementary support system. FIG. 3B is a cross-sectional schematicview of an alternative supplementary support system. FIG. 3C is a topschematic view of the supplementary support system. The figures will bedescribed in conjunction with each other. Elements with similar numbersas described above are similarly used herein. Generally, the pile 2 isinstalled in the sea floor 4. A sleeve 20 is installed and coupled withthe pile 2. A coupling member 36 is coupled between the sleeve 20 and astructure 38.

In some instances, the support provided by the pile 2 may be inadequatefor the particular load on the coupling member 36, even with a sleeve20. To supplement the stability of the pile 2 to provide additionalloading, other support structures may be used.

To add the supplementary support, a supplemental pile 40 may beinstalled at some desired distance from the pile 2. In at least oneembodiment, a coupling member 44 can be used with the supplemental pile40, such as in a lower portion of the pile 40, to provide the additionalsupport to the pile 2 with the sleeve 20. The sleeve 20 can include anadditional padeye 43 that provides a coupling location for the couplingmember 44 from the sleeve 20 to the pile 40. The coupling member 44disposed between the sleeve 20 and the pile 40 could be aligned in anopposite direction from the coupling member 36 disposed between the pile2 and the structure 38. Generally, such supplementary support structureswill be positioned at a non-zero angle “α” relative to the couplingmember 36, as shown in FIG. 3C, and advantageously between about 90° toabout 270°. Alternatively or in addition thereto, if a sleeve 42 isinstalled on the pile 40, a coupling member 46 may be coupled betweenthe sleeve 20 and the sleeve 42.

As shown in FIG. 3B, an anchoring member 48 may be used as analternative to the supplemental pile 40. The anchoring member 48 may bea structure embedded into the sea floor and generally shaped to providegreater resistance in at least one direction than another. The anchoringmember 48 can provide resistance to movement of the pile 2 and thesleeve 20 caused by a force from the coupling member 36. The sleeve 20may include an additional padeye 43 to couple a coupling member 46between the sleeve 20 and the anchoring member 48.

If additional piles are installed such as piles 42A, 42B shown in FIG.3C, then the piles can be installed at some non-zero angle, such asangles αA and αB, respectively. One or more padeyes 43A and 43B,respectively, can be used to couple one or more coupling members to thepile 2 and/or sleeve 20.

FIG. 4 is a perspective schematic view of another embodiment of thesleeve. The sleeve 20 can include an assembly of two or more ringscoupled together with one or more longitudinal members. It is believedthat the assembly of the sleeve shown in FIG. 4 is lighter in weightthan a correspondingly sized solid outer shell sleeve. The assembly mayalso provide less friction due to less surface area, as the sleeve isinstalled over the pile, in surrounding layers of material in the seafloor 4.

More specifically, the sleeve 20 can include an upper sleeve ring 50 anda lower sleeve ring 52 with at least one longitudinal member 56 coupledtherebetween. The longitudinal member 56 generally extends outward fromthe rings by a portion of the longitudinal member 56, herein termed anextension portion 58. The extension portion 58 can include fins, websportions of formed structures, and so forth. Generally, more than onelongitudinal member may be used to support the rings around the sleeveperimeter. For example, three longitudinal members are shown, but thenumber of longitudinal members can vary from one to many. Thelongitudinal member 56 may further include a pointed end to helpfacilitate installation in the sea floor 4 shown in FIG. 2. Further, thelongitudinal member may also assist in maintaining rotational alignmentas the sleeve is embedded in the sea floor 4 materials. In general, thelongitudinal member 56 has sufficient strength to avoid undue bending ofthe sleeve 20 at least during installation, so that the sleeve will notbind on the pile 2 as it is installed. Further, the sleeve 20 caninclude an intermediate sleeve ring 54. The intermediate sleeve ring 54can further assist in maintaining alignment and avoiding buckling of theassembly at least during installation of the sleeve on the pile. A top60 of the sleeve 20 may be at least partially open. In general, the topis used to limit the amount of travel of the sleeve downward over thepiles.

The lower sleeve ring 52 generally includes a padeye 24. The padeye 24is formed of a section 64 that extends radially outward relative to alongitudinal axis 57 that passes through an inner portion of the rings.The padeye generally has an opening 66 formed therethrough, generallyused to couple the coupling member 36 thereto, shown in FIG. 2. In someembodiments, the padeye can further include a padeye clearance portion62 that is open to the internal portion of the ring 52. The padeyeclearance portion 62 can be sufficiently sized, so that the ring 52 canbe installed over the original padeye 14 of the pile 2, such as shown inFIG. 2.

The one or more rings 50, 52, 54 are generally spaced a distance fromeach other in the sleeve 20, shown in FIG. 4. For example, the rings 50,54 can be separated by a spacing 68, and the rings 54, 52 can beseparated by a spacing 70. The spacing, and absence of ring material inthe spacing, may provide less friction between the sleeve 20 and thelayers of material in the sea floor 4 through which the sleeve isinstalled.

FIG. 5 is a side schematic view of an alternative embodiment of thesleeve shown in FIG. 4. FIG. 6 is a top schematic view of a lower ringshown in FIG. 5. FIG. 7 is a top schematic view of an upper ring shownin FIG. 5. The drawings will be described in conjunction with eachother. Similar elements as described above will be used herein.Generally, the sleeve 20 can include a number of rings, such as rings50, 52 and 54, coupled together with one or more longitudinal members56. The spacings 68, 70 between the rings can provide openings to thesubsea conditions, and to the sea floor material. A sleeve padeye 24extends radially outward from the sleeve 20 and is generally coupled tothe lower sleeve ring 52. The padeye 24 includes a section 64 and anopening 66 extending therethrough.

As shown in FIG. 6, the lower ring 52 can be extended outwardly relativeto the pile 2 with a padeye extension 74 to a suitable radial locationfor the padeye 24 to be coupled thereto. The pile 2 relative to the ring52 is shown for reference, but it is understood that other variationsare possible and contemplated. In some embodiments, it may be conduciveto couple a longitudinal member 56 to the extension 74 on one or bothsides of the padeye 24.

As shown in FIG. 7, the upper ring 50, shown disposed about the pile 2for reference, can include an extension 76 disposed radially outwardfrom the pile. The extension 76 can provide support for the one or morelongitudinal members extending to the ring 52 and aligned therewith.

FIG. 8 is a perspective schematic view of another embodiment of thesleeve. In some instances, the sleeve 20 may be completely enclosed,with the exception of the base which is open, should suction pressure berequired to drive the sleeve to depth on the pile 2.

In operation, the sleeve 20 can be used to rehabilitate a pile 2 that isinstalled into the sea floor 4. Generally, the pile would beinvestigated for a variety of conditions of the pile and a determinationmade of any degradation that would significant impact the ability of thepile to support a load, or otherwise indicate that the installation of asleeve is appropriate. Based on that determination, the sleeve could beinstalled over the pile.

Generally, the sleeve 20 is positioned adjacent to the pile 2, if thepile was already installed into the sea floor 4. The sleeve padeye 24 isaligned with the pile padeye 24, and the sleeve is allowed to be loweredover the pile. The sleeve can be driven over the pile or lowered overthe pile through its own weight. In general, the sleeve is maintained inrotational alignment with the pile, so that the sleeve padeye is in asimilar position as a pile padeye after installation. The sleeve thenbecomes a substitute for the purpose of the pile without necessitatinginstalling a new pile to replace the former pile. If desired, groutingmay be installed between the sleeve and the pile. The coupling membercan be coupled to the sleeve padeye generally prior to installation overthe pile, or, in some circumstances, after installation. If desirable ornecessary, the sleeve can be locked to the pile.

In some circumstances, it may be desirable to pre-install the sleeve 20on the pile 2 prior to installation of the pile into the sea floor 4,such as in a new installation. Such circumstances are envisioned andencompassed with the scope of the present claims and disclosure. Forexample, it is foreseen that periodic replacements of the pile may beappropriate and a preinstalled sleeve may be easier to replace on aperiodic basis starting with the preinstalled sleeve.

The systems and methods herein have been described in the context ofvarious embodiments and not every embodiment has been described.Apparent modifications and alterations to the described embodiments areavailable to those of ordinary skill in the art. The disclosed andundisclosed embodiments are not intended to limit or restrict the scopeor applicability of the concepts of the Applicants, but rather, inconformity with the patent laws, Applicants intend to protect all suchmodifications and improvements to the full extent that such falls withinthe scope or range of equivalent of the following claims.

The various methods and embodiments of the concept may be included incombination with each other to produce variations of the disclosedmethods and embodiments, as would be understood by those with ordinaryskill in the art, given the understanding provided herein. Also, variousaspects of the embodiments could be used in conjunction with each otherto accomplish the understood goals of the disclosure. Also, thedirections such as “top,” “bottom,” “left,” “right,” “upper,” “lower,”and other directions and orientations are described herein for clarityin reference to the figures and are not to be limiting of the actualdevice or system or use of the device or system. Unless the contextrequires otherwise, the word “comprise” or variations such as“comprises” or “comprising,” should be understood to imply the inclusionof at least the stated element or step or group of elements or steps orequivalents thereof, and not the exclusion of a greater numericalquantity or any other element or step or group of elements or steps orequivalents thereof Discussion of singular elements may include pluralelements and vice-versa. References to at least one item followed by areference to the item may include one or more items. The device orsystem may be used in a number of directions and orientations. The term“coupled,” “coupling,” “coupler,” and like terms are used broadly hereinand may include any method or device for securing, binding, bonding,fastening, attaching, joining, inserting therein, forming thereon ortherein, communicating, or otherwise associating, for example,mechanically, magnetically, electrically, chemically, directly orindirectly with intermediate elements, one or more pieces of memberstogether and may further include without limitation integrally formingone functional member with another in a unity fashion. The coupling mayoccur in any direction, including rotationally.

The order of steps may occur in a variety of sequences unless otherwisespecifically limited. The various steps described herein may be combinedwith other steps, interlineated with the stated steps, and/or split intomultiple steps. Additionally, the headings herein are for theconvenience of the reader and are not intended to limit the scope of theconcept. Other and further embodiments utilizing one or more aspects ofthe concepts described above may be devised without departing from thespirit of Applicants' disclosure. For example, other types of pilescould be used and some piles could have different types of padeyes oreven no padeyes. Other variations are contemplated given the teachingsof the disclosure herein.

Further, any references mentioned in the application for this patent, aswell as all references listed in the information disclosure originallyfiled with the application, are hereby incorporated by reference intheir entirety to the extent such may be deemed essential to support theenabling of the concept. However, to the extent statements might beconsidered inconsistent with the patenting of the concept, suchstatements are expressly not meant to be considered as made by theApplicant(s).

1. A method for rehabilitating a pile installed, or partially installedinto a sea floor, comprising: positioning a pile sleeve having a padeye;allowing the pile sleeve to be lowered over the pile; and securing thesleeve to the pile.
 2. The method of claim 1, wherein the pile comprisesa padeye and further comprising: aligning the sleeve padeye with thepile padeye prior to installing the sleeve over the pile; andmaintaining alignment as the sleeve is lowered over the pile.
 3. Themethod of claim 1, wherein maintaining alignment as the sleeve islowered over the pile comprises guiding the sleeve into the sea floorwith at least one longitudinal member extending outward from the sleeve.4. The method of claim 1, wherein the pile is installed or partiallyinstalled into a sea floor prior to installing the sleeve over the pile.5. The method of claim 1, further comprising installing the sleeve overthe pile prior to installing the pile at least partially into the seafloor.
 6. The method of claim 1, further comprising: investigating acondition of an existing pile installed or partially installed in thesea floor; determining a degraded condition; and installing the sleeveover the pile based on determining the degraded condition.
 7. The methodof claim 1, further comprising: installing a supplemental pile; andcoupling the supplemental pile to the sleeve at a non-zero anglerelative to the coupling member between the structure and the sleevepadeye.
 8. The method of claim 1, further comprising: installing ananchoring member; and coupling the anchoring member to the sleeve at anon-zero angle relative to the coupling member between the structure andthe sleeve padeye.
 9. The method of claim 1, further comprising lockingthe sleeve to the pile.
 10. The method of claim 1, wherein the pilecomprises a suction pile.
 11. A rehabilitation system for a subsea pile,the pile to be adapted being installed or partially installed into a seafloor, the system comprising: a sleeve having a outer shell forming aninterior volume and at least partially open on a bottom of the sleeve; apadeye coupled to the sleeve, the padeye having a section of materialcoupled to the sleeve with an opening disposed through the material; andthe sleeve being adapted to be inserted over a pile.
 12. The system ofclaim 11, wherein the sleeve comprises an assembly of at least two ringscoupled together with at least one longitudinal member, the rings beingspaced apart from each other.
 13. The system of claim 12, wherein thelongitudinal member extends outward from the rings and is adapted toguide the sleeve in rotational alignment to the existing pile.
 14. Thesystem of claim 12, further comprising one or more intermediate ringscoupled between the two rings and longitudinally spaced apart from eachof the two rings.
 15. The system of claim 12, wherein the sleevecomprises at least two longitudinal members spaced about a periphery ofthe rings.
 16. The system of claim 11, wherein the sleeve comprises anextended padeye having an opening extending radially from an innerportion of the ring, the opening sized to extend around an existingpadeye on the existing pile.
 17. The system of claim 11, wherein thesleeve comprises a top being at least partially open, the top comprisinga locking system adapted to couple the sleeve to the pile.
 18. Thesystem of claim 11, further comprising at least one secondary padeyedisposed on the sleeve and rotationally located at a non-zero anglerelative to the padeye of the sleeve.
 19. The system of claim 18,wherein the secondary padeye is coupled to an anchor, a supplementalpile, or a combination thereof
 20. The system of claim 11, furthercomprising a supplemental pile coupled to the sleeve.